About Entity-to-Data-Element Advanced Mapping XQuery Expressions

This topic describes how to use the Mapping Rule editor, Mapping tab, Mapping subtab Mapping Rule Item area, XQuery subtab to write an expression that defines an advanced mapping between an entity and a data element. This field is displayed when you select the target of an entity-to-data-element mapping and select the Advanced radio button in the Mapping Rule Item topic.

Context: The input document is a source order item.
Prolog: There is no prolog for this XQuery.
Body: The XQuery body returns a data element value or returns () to leave the current value unchanged.

The following example shows an XQuery expression that returns "Y" if a particular parameter exists, and () if it does not exist.

if fn:exists(vf:instance("checkMe")/somevalue) 
   "Y"
else 
   ()